[SOLVED] Python Parallel-SSH Tunnel

Issue

I'm trying to use parallel-ssh to setup a simple ssh tunnel. (I'm not able to use the sshtunnel package due to its dependencies.)

What I expect to happen is that once the tunnel is created I can arbitrarily connect/disconnect sockets to the matching port, but that's not working.

Can someone clarify why the below code can successfully connect the client over ssh, but doesn't allow the socket to connect?

The error message from the socket is:

ConnectionRefusedError: [Errno 111] Connection refused

Example code:

from pssh.clients import SSHClient
from pssh.clients.native.tunnel import TunnelServer
import socket

client = SSHClient(REMOTE_IP, UNAME)

serv = TunnelServer(client, HOST, PORT, bind_address=HOST)
serv.start()

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((HOST, PORT))

Solution

Through a bit of trial, error, and reviewing the source code I found a solution:

1. Instead of serv.start() call serv.serve_forever()
2. Run it in a thread
3. The port that the new socket connects to is the serv.listen_port

None of this was made clear via the documentation, unfortunately.

Example working class:

from pssh.clients import SSHClient
from pssh.clients.native.tunnel import TunnelServer
import threading, time

class PsshTunnel:
    def __init__(self, remote_ip, username, host="localhost", port=8080):
        self.remote_ip = remote_ip
        self.username = username
        self.host = host
        self.port = port

    def _run(self):
        client = SSHClient(self.remote_ip, self.username)

        self.serv = TunnelServer(client, self.host, self.port, bind_address=self.host)
        self.serv.serve_forever()

    def start(self):
        self.th = threading.Thread(target=self._run, daemon=True)
        self.th.start()
        # Give it time to connect
        time.sleep(3)

    def stop(self):
        self.serv.stop()

    @property
    def socket_port(self):
        return self.serv.listen_port

Answered By - Mandias

Answer Checked By - Katrina (WPSolving Volunteer)